English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The principal objective of this work is to report on the power coupled to atungsten target in the Proto-MPEX device during oblique injection of amicrowave beam (< 70 kW at 28 GHz) into a high-power (~100 kW at 13.56 MHz)over-dense (n_e>1E10^19 m^(-3)) deuterium helicon plasma column. Theexperimental setup, electron heating system, electron heating scheme, and IRthermographic diagnostic for quantifying the power transport is described indetail. It is demonstrated that the power transported to the target can beeffectively controlled by adjusting the magnetic field profile. Using thismethod, heat fluxes up to 22 MWm-2 and power transport efficiencies in therange of 17-20% have been achieved using 70 kW of microwave power. It isobserved that most of the heat flux is confined to a narrow region at theplasma periphery. Ray-tracing calculations are presented which indicate thatthe power is coupled to the plasma electrons via an O-X-B mode conversionprocess. Calculations indicate that the microwave power is absorbed in a singlepass at the plasma periphery via collisions and in the over-dense region via2nd harmonic cyclotron resonance of the electron Bernstein wave. The impact ofthese results is discussed in the context of MPEX.

Power transport efficiency during O-X-B 2nd harmonic electron cyclotron heating in a helicon linear plasma device